The surface compositions of potassium and copper containing Fe/Mn oxide Fischer-Tropsch catalysts were investigated by XPS and ISS. The calcined samples showed a surface enrichment in Mn and K, the Cu surface content equals the bulk concentration. The surface species in the calcined samples are identified as Fe 2O 3, Mn 2O 3, MnO 2, CuO and, most probably, KO 2. After reduction we have Fe°, Fe(II) and Fe(III) oxide, MnO, Cu° and KOH on the surface of the samples. The Cu surface concentration is not changed by reduction, but small amounts of Cu lead after reduction to a strong surface enrichment in Mn and a decrease in Fe concentration. A strong increase in the potassium surface content is observed after reduction. ISS measurements of the latter samples show that the potassium enrichment is confined to the outmost layers. The degree of reduction of Fe is increased by K and Cu, but only with Cu an increase in the surface concentration of Fe° is observed. These results can be used to predict catalytic activity in Fischer-Tropsch synthesis.